This is what it looks like on a real switch: Above you see that it‟s checking the flash drive of the switch. Next step is to load the IOS image that it found on the flash drive.

IOS images are stored on the flash drive in a compress format, it will be uncompressed and copied to the RAM of the switch.

Now IOS is loaded you will see something like this, you see this banner and the IOS version that I‟m running. This is a Cisco 3560 switch.

IOS will check the flash drive.

And once it's done it will do a POST (Power On Self-Test):

Once the POST is done we'll get a final warning:

And finally you'll see an overview of the hardware that this switch offers.

Once the switch is done you finally get to see this message:

Press RETURN to get started!

If the switch does not have a configuration, you'll see the following:

—- System Configuration Dialog —-
Would you like to enter the initial configuration dialog? [yes/no]:

If you type yes and press enter it will walk you through a wizard where you can configure some basic settings.

I'm going to skip it since we'll configure everything ourselves.

Right now you are in user mode.

You can recognize it because of the > symbol. When you are in user mode you don't have full access to the device. What we want is privileged mode which is also known as enable mode.

This is how we do it.

That's it! We are now in privileged mode where we have full access to our device. You can recognize it because of the # symbol.

If I want to return back to user mode I can do this.

Let's start with a simple example. We'll configure the clock on our switch so I can demonstrate how the CLI works:

Whenever I partially type a command I can use the ? to see my options.

I typed in “cl?” and the CLI tells me that there are two commands that start with the letters “cl”. There's the
“clear” command and the “clock” command.